The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Rechargeable batteries are used in many applications. The applications may range from portable electronic devices to industrial equipment. For example, the portable electronic devices may include cell phones, cameras, personal digital assistants (PDAs), laptop computers, and notebook computers. The industrial equipment may include fork-lifts, hybrid-electric vehicles, medical equipment, and uninterruptible power supplies.
Rechargeable batteries typically include cells that utilize different chemical technologies and that generate different output voltages. For example, Nickel-Cadmium (NiCd) and Nickel Metal Hydride (NiMH) cells generate an output voltage of 1.2 volts (1.2V). Lithium ion cells generate output voltages ranging from 3.6V to 3.9V.
Many applications utilize voltages that may be greater than the output voltage generated by a single cell. Accordingly, a battery stack of multiple cells may be used to generate output voltages that are greater than the voltage generated by a single cell. For example, a battery stack comprising two cells may generate an output voltage that can power some portable electronic devices. A battery stack comprising hundreds of cells may generate an output voltage that can power some electric vehicles.